A comparison of the relative merits of changes in ventilation-perfusion relationships, in pulmonary vascular resistance and in pulmonary arterial input impedence in assessing pulmonary vasomotion will be made in patients with chronic diffuse interstitial lung diseases. More sensitive techniques for assessment of respiratory muscle function will be developed and the usefullness of ventilatory aids in supporting muscle function examined in patients with chronic thoracopulmonary and neuromuscular diseases. The role of muscle myoglobin in supporting oxygen consumption and muscle performance under hypoxic conditions will be examined during active contraction in a muscle group of changing conditions of oxygen supply and extreme hypoxia will be investigated. Observations on the oxygen consumption of heart cells under hypoxic conditions will be continued. Methods for quantifying the binding of labelled univalent Fab fragments to membrane bound angiotensin converting enzyme in vivo will be developed. Fab fragments will also be tested in vivo to document that these fragments do not produce the immune injury which results from the use of the intact antibody against angiotensin converting enzyme. Studies of beta-adrenergic receptors and catecholamine-sensitive adenylate cyclase in erythrocytes and cultured endothelial cells will continue.